gcov: Add gcov data struct to sysfs

Extracting the skiboot gcov data is currently a tedious process which
involves taking a mem dump of skiboot and searching for the gcov_info
struct.
This patch adds the gcov struct to sysfs under /opal/exports. Allowing the
data to be copied directly into userspace and processed.

Signed-off-by: Matt Brown <[email protected]>
[stewart: refactor to dump out whole skiboot area, as gcov data is all over]
Signed-off-by: Stewart Smith <[email protected]>

Author: m-brow

core/gcov-profiling.c

@@ -89,7 +89,6 @@ void skiboot_gcov_done(void)
 	printf("GCOV: gcov_info_list at 0x%p\n", gcov_info_list);
 }
 
-
 void __gcov_merge_add(gcov_type *counters, unsigned int n_counters)
 {
 	(void)counters;

core/opal.c

@@ -347,6 +347,10 @@ static void add_opal_firmware_exports_node(struct dt_node *node)
 	dt_add_property_u64s(exports, "symbol_map", sym_start, sym_size);
 	dt_add_property_u64s(exports, "hdat_map", SPIRA_HEAP_BASE,
 				SPIRA_HEAP_SIZE);
+#ifdef SKIBOOT_GCOV
+	dt_add_property_u64s(exports, "gcov", SKIBOOT_BASE,
+				HEAP_BASE - SKIBOOT_BASE);
+#endif
 }
 
 static void add_opal_firmware_node(void)